Yuki Kimoto's Perl Blog

FFI::Platypus is interesting. It seems like real FFI module for Perl 5.

FFI is foreign function interface. This is a little slow than XS, but you can call C/C++ library without C code.

I saw some FFI module for perl 5, FFI, or FFI::Raw, but not enough to create C extension flexibly.

FFI::Platypus seems like excelent module because you can call any C/C++ library using its features.

FFI::Platypus/CPAN

I try some example. All work well.

  use FFI::Platypus;
 
  my $ffi = FFI::Platypus->new;
  $ffi->lib(undef); # search libc

  # call dynamically

  $ffi->function( puts => ['string'] => 'int' )->call("hello world");

  # attach as a xsub and call (much faster)

  $ffi->attach( puts => ['string'] => 'int' );

  puts("hello world");

You can also create C structure in Perl code by using "record_layout" method.

  package My::UnixTime;

  use FFI::Platypus::Record;

  record_layout(qw(

     int    tm_sec

     int    tm_min

     int    tm_hour

     int    tm_mday

     int    tm_mon

     int    tm_year

     int    tm_wday

     int    tm_yday

     int    tm_isdst

     long   tm_gmtoff

     string tm_zone

  ));

  my $ffi = FFI::Platypus->new;

  $ffi->lib(undef);

  # define a record class My::UnixTime and alias it to "tm"

  $ffi->type("record(My::UnixTime)" => 'tm');

  # attach the C localtime function as a constructor

  $ffi->attach( localtime => ['time_t*'] => 'tm', sub {

   my($inner, $class, $time) = @_;

   $time = time unless defined $time;

   $inner->(\$time);

  });

  package main;

  # now we can actually use our My::UnixTime class

  my $time = My::UnixTime->localtime;

  printf "time is %d:%d:%d %s\n",

   $time->tm_hour,

   $time->tm_min,

   $time->tm_sec,

   $time->tm_zone;

If you use FFI::TinyCC module, you can write C code and execute it by jit.

  use FFI::TinyCC;
  use FFI::Platypus::Declare qw( int );

  my $tcc = FFI::TinyCC->new;

  $tcc->compile_string(q{

   int

   find_square(int value)

   {

     return value*value;

   }

  });

  my $address = $tcc->get_symbol('find_square');

  attach [$address => 'find_square'] => [int] => int;

  print find_square(4), "\n"; # prints 16

If you don't know FFI module for perl5, it is worth using FFI::Platypus
.

FFI::Platypus is new project. Its development start from 2015-01-07.
I didn't know until a few weeks ago.

If you are interesting FFI::Platypus, let's share it on GitHub.

FFI::Platypus/Github

I think good project should get a lot of evaluation.

For example, ruby ffi is shared over than 1200.

ruby people share their projects positively.
The ruby people personality that "Let's share more projects! Open source programmer need more evaluation" is good.

FFI::Platypus is yet new, but good project.
If you plan to use FFI in the feature, let's try to use and share it!

FFI::Platypus/Github